code: def __iter__(self):
      ...
  
file_path: NeMo/nemo/collections/nlp/data/language_modeling/megatron/data_samplers.py
imports: import abc
  from itertools import chain
  from typing import Optional
  import torch
  from nemo.utils import logging
label_desc: Use image node_id 3 for calling the BaseMegatronSampler obj's underlying member method code with example usage: obj.__iter__() without return types